Toothbrush Timer With Mathquiz

This was my first Arduino project, and since the prototype was quite a success with the children, I soldered a permanent version. Since our bathroom has no accessible power plug, I made it battery powered. Brushing the teeth is expected to take 130 seconds: 30 seconds each for each corner and 10 seconds for the tongue. An animated toothbrush reminds which stage you are. After one minute a true/false math question will be asked. Only by answering correctly and continuing to the end a point will be earned. The difficulty of the math questions will go up when 4 questions have been answered correctly (or down after two consecutive mistakes). The scores and levels are kept in EEPROM for 4 users.”